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Xi Z.,Nanjing Southeast University | Xi Z.,Yangtze University | Huang R.,Nanjing Southeast University | Li Z.,Nanjing Southeast University | And 7 more authors.
ACS Applied Materials and Interfaces | Year: 2015

Aptamers are short single-stranded DNA or RNA oligonucleotides and can be selected from synthetic combinatorial libraries in vitro. They have a high binding affinity and specificity for their targets. Agarose gels, nitrocellulose membranes, and adsorptive microplates are often used as carriers to immobilize targets in the SELEX (systematic evolution of ligands by exponential enrichment) process, but the subsequent separation step is tedious and time-consuming. Therefore, we used magnetic nanoparticles (MNPs) as carriers to immobilize the target, hepatitis B surface antigen (HBsAg), which is convenient for fast magnetic separation. In this study, we first selected DNA aptamers against HBsAg by immobilizing HBsAg on the surface of carboxylated MNPs. The ssDNA library of each selection round was prepared by asymmetric PCR amplification for the next selection round. To obtain aptamer sequences, the final selected products were purified by gel electrophoresis, then cloned, and sequenced. DNA aptamers that specifically bind to HBsAg were successfully obtained after 13 selection rounds. The selected aptamers were used to construct a chemiluminescence aptasensor based on magnetic separation and immunoassay to detect HBsAg from pure protein or actual serum samples. There was a linear relationship between HBsAg concentration and chemiluminescent intensity in the range of 1-200 ng/mL. The aptasensor worked well even in the presence of interfering substances and was highly specific in the detection of HBsAg in serum samples, with a detection limit 0.1 ng/mL lower than the 0.5 ng/mL limit of an ELISA in use at the hospital. This aptasensor can contribute to better detection of hepatitis B virus infection. © 2015 American Chemical Society.

Jin J.,Getein Biotechnology Co. | Jin L.,Getein Biotechnology Co. | Su E.-B.,Getein Biotechnology Co.
CrystEngComm | Year: 2014

A new centrosymmetric one-dimensional ABX3-type organic-inorganic hybrid polymer compound ([C5H6N+][CdBr3]-) was synthesized and separated into block colorless crystals. DSC and dielectric measurements indicate that this compound undergoes a reversible phase transition at 230 K with a hysteresis width of 17.9 K. The crystal structures, determined at 293(2) K and 140(2) K, show that the phase transition is a type of isosymmetric change from the space group of Pbca (no. 61) in the low-temperature phase (LTP) to the space group of Cmcm (no. 63) in the room-temperature phase (RTP). The main difference between the LTP and the RTP structures is the distribution of the nitrogen atoms in the pyridinium cations. In the LTP, pyridinium cations are well ordered with localized N and C atom positions. Meanwhile, for the RTP, the N atoms are indistinguishable from the C3 atoms with the occupancy of N/C3 atoms being 0.5, separately. Noncovalent static attracting forces (Coulombic and van der Waals forces) and nonclassical C-H⋯Br and N-H⋯Br hydrogen-bond interactions stabilize the crystal structure. This journal is © the Partner Organisations 2014.

Mou X.,Nanjing Southeast University | Li T.,Nanjing Southeast University | Wang J.,Nanjing Southeast University | Ali Z.,Nanjing Southeast University | And 13 more authors.
Journal of Biomedical Nanotechnology | Year: 2015

With the help of Fe3O4 nagnetic nanoparticles as a solid carrier and an excellent tool for separation, six SNP loci (rs2279115 of BCL2 gene, rs804270 of NEIL2 gene, rs909253 of LTA gene, rs2294008 of PSCA gene, rs3765524 and rs10509670 of PLCE1 gene) were selected to evaluate their relation to gastric cancer risk. Using two kinds of functionalized magnetic nanoparticles and universal tagged arrays, the whole operation procedure including genome DNA extraction and SNP genotyping was performed. All genotypes and allele frequencies were calculated in the cases and controls respectively to analyze their association with gastric cancer risk. Totally 200 pathological samples and 134 normal control subjects were collected. The results demonstrated that four SNP loci (rs2279115, rs804270, rs909253 and rs3765524) showed a potential association with gastric cancer risk, and the other two (rs2294008, rs10509670) possessed no difference/association among cases and controls. © 2015 American Scientific Publishers All rights reserved.

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